Sandwich slab construction and anchor therefor

ABSTRACT

A sandwich-slab structure has a front concrete plate and a rear concrete plate which are generally coextensive and sandwich a layer of insulating material, e.g., a sheet or plate of foamed synthetic resin, between them. The layer of insulation is traversed by a plurality of connectors or anchors in the form of tubules or sleeves having opposite ends received in the concrete plates and provided with transverse formations for anchoring the sleeve in each concrete plate, preferably by engagement with a reinforcing mat.

1 1 Sept. 11,1973

llnited States Patent 1 Haeussler [54] SANDWICH SLAB CONSTRUCTION AND1,661,044 2/1928 Lawrence 52/565 1,072,361 9/1913 52/706 X 1,879,31952/405 X 2,063,309 2,309,147 2,633,439

Rickman......

ANCHOR THEREFOR 9/1932 Kleitz....... 12/1936 Graef..,........

[76] Inventor: Ernst I-Iaeussler, Grashofstr 47, 43

Essen-Bredeney, Germany Feb. 22, 1971 Wilkinson Konstandt..........

[22] Filed:

Primary Examiner Alfred C. Perham Att0rneyKarl F. Ross [21] Appl. No.:117,673

[30] Foreign Application Priority Data Feb. 24, 1970Germany......,,...........

ABSTRACT 68 6 O 56 %08@ 4/246 yz ,y 5 4wwm5 00 M 5 2 3/ 0 7 2 36 5 w w 5m 0 0 NW 2 NW6 5 m5 m WW2 m0 3 m u u 00 m Mme m m "s8 h n 3 1 1m r d n UIF H UN 5 55 [56] References Cited and provided with transverseformations for anchoring UNITED STATES PATENTS the sleeve in eachconcrete plate, preferably by engage ment with a reinforcing mat.

3,383,817 5/1968 Gregori.....,..................,........52/3092,964,821 12/1960 Meehan 52/410 X 6 Claims, 8 Drawing Figures Cd/VCEETFPATENTEDSEPI Hers sum 1 BF .3

3 came/e575- SANDWICH SLAB CONSTRUCTION AND ANCHOR THEREFOR FIELD OF THEINVENTION The present invention relates to a sandwich-slab construction,especially for the prefabricated and semifabricated erection of concretestructures, to a connector or anchor for the members of a sandwich-slabstructure and to a system for assembling a sandwich slab; moreparticularly, the invention relates to an improved assembly of the typewherein a pair of concrete plates are interconnected in spacedrelationship and sandwich an insulating layer between them.

BACKGROUND OF THE INVENTION With increasing efforts to reduce the costof construction, various proposals have been made with respect tocomposite wall, slab and plate structures. In general, a composite orlaminar structure for construction purposes will comprise a number oflayers tied together in a more or less rigid manner, each layercontributing some characteristic to the overall properties of the plate.For example, the sandwich or laminar structure may comprise one or morefacing members defining an outer surface of the structure to provide anaesthetic appearance or a desired texture, one or more load-supportingmembers adapted to support the laminar structure or a suitable carrieror frame or adapted to support another structure on the plate, one ormore insulating members or layers designed to resist heat transferbetween the inner and outer surfaces of the slab, and one or more coreor filler members adapted to provide the desired bulk. It will beevident that one or more of these members can be eliminated, dependingupon the physical or aesthetic properties desired or additional members,e.g., sound-insulating layers, may be provided if certain qualities areto be enhanced.

While such laminar constructions have found widespread acceptance wherethe members were constituted of pressed fiber (fiberboard or hardboard), metal, synthetic resin or wood have constituted the members,only of late has a composite concrete slab construction of the sandwichtype been successful. A sandwich slab of concrete, which may be used forwalls, partitions, load-supporting members, floors, ceilings and roofsof buildings, generally comprises a pair of reinforced-contreteplates'flanking a layer of thermal insulation and sound insulation andheld together by anchors which traverse the insulating layer and tie theconcrete plates together. The concrete plates and the insulating layerare coextensive or substantially coextensive, i.e., have geometricallycongruent outlines and are usually rectangular. The sandwich slab may befabricated at a factory or plant remote from the construction site, maybe transported thereto by any convenient conveyers, and may be erectedat the site with cranes or the like. In practice, such slabs aregenerally anchored by bolts, pins, studs, welding or adhesives to asupport frame which may be cast from concrete in situ or which may beerected from steel or the like.

The concrete plates constituting the sandwich slab are reinforced, asnoted earlier, and may be provided with a lattice-work of reinforcingbars, rod or wire, previously tied, welded or otherwise joined to form areinforcing mat. The reinforcing members are generally constituted ofsteel.

The insulating layer may, of course, be of any of the types accepted inconcrete-slab construction and is preferably a relatively rigid plate orsheet. A foamed synthetic resin, e.g., cellular polystyrene, is typicalfor this layer.

It has hitherto been the practice in the manufacture of suchsandwich-slab construction to anchor the reinforcing mat of one concreteplate to the reinforcing mat of the other concrete plate through theinsulating layer with, for example, reinforcing rod or wire of M-configuration. Of course, other systems for typing the plates togetherhave been proposed but these, along with the connecting systemspecifically described, have proved to be unsatisfactory in certainrespects. As will be apparent, the concrete slabs are subject to manystresses which not only are extreme, but which may vary over short andlong periods of time. For example, from day to night, the slabs aresubjected to substantial temperature differentials and variations intemperature and from summer to winter, a major variation in temperatureis applied to the slab. The effect of temperature differential will beunderstood more readily when it is recognized that one concrete plate ofthe sandwich slab may be exposed predominantly to the outsidetemperature while the other concrete plate is exposed to thetemperatures within the structure. The temperature variations have beenfound to detrimentally affect the connection between the concrete slabs.Furthermore, the aforementioned systems for tying the concrete slabstogether have the disadvantage that the insulating layer, which may bepreformed with openings traversed by the tie members, must be preparedwith care; the tie members are generally insufiiciently strong tomaintain a force-transmitting connection between the concrete plates,etc.

OBJECTS OF THE INVENTION in assembly and mounting than has hitherto beenthe case.

It is another object of this invention to provide an anchor forconnecting concrete plates of a sandwich-slab structure such that thedisadvantages enumerated above are obviated.

SUMMARY OF THE INVENTION These objects and others which will becomeapparent hereinafter, are attained in accordance with the presentinvention in a system for anchoring a front concrete plate to a rearconcrete plate in substantially juxtaposed and coextensive relationship,through an insulating layer interposed between these plates, wherein theanchor comprises an elongated tubule or sleeve provided at oppositeextremities received in the respective concrete plates with meansengaging them. Such means is preferably located adjacent each edge ofthe sleeve. According to an important feature of this invention, thetubules or sleeves are tube or pipe sections of a regular cross-section,Le, a cross-section corresponding to that of a conic section or aregular polygon, and preferably which is constant over the entire lengthof the anchor although it has been found to be advantageous in certaincircumstances to provide a constant convergence to the anchor. In thelatter case, the anchor sleeve is conical, the conicity assisting inanchoring the concrete plates together.

According to another feature of this invention, the means at each end ofthe sleeve include arrangements engageable with the reinforcing membersof the respective concrete plates and it is preferred to providelattice-like reinforcements for the latter. In this case, the anchor isdimensioned to extend into an interstice of the reinforcing lattice ofeach concrete slab and to be provided with laterally outwardly extendingformations engageable behind the reinforcing rod or members of thelatticework. I

According to a more specific feature of this invention, the anchorsleeves are formed with rows of holes or perforations proximal to theirends while the aforementioned formations receive bars or rods traversingthese holes and projecting laterally beyond each anchor to overhang orunderlie a reinforcing rod or bar of the lattice. Advantageously, twolongitudinally spaced rows of such holes are provided and at least onerod is fitted into each row of holes so that the transverse rods engageon opposite sides of the reinforcing mats. Each row of holes willgenerally include a number of pairs of diametrically oppositeperforations which are aligned to permit the transverse rod to extendthrough them.

In addition or in the alternative, the means for locking the sleeveswithin the concrete plates can include tabs or lugs which may be bentoutwardly to project laterally.

Still another object of the invention resides in the insertion into thesleeve of a plug of insulating material to prevent thermal lossesthrough these anchors. The plug may be punched from the insulating platein the formation of the opening through which the: anchor is to extendand the punching may be effected by driving the sleeve into theinsulating layer at the time the sleeve is mounted, the plug ofinsulating material remaining within this sleeve. While the anchor isconstituted of metal, preferably steel, and may be cut from a pipe ortube or built up from steel plates or bent from sheet metal, othermaterials may be used according to the physical properties desired.

The system of the present invention provides a large effective diameterlinking the two concrete plates and hence involves a force-transmissionwhich is distributed over a large area by virtue of the large diameterand cross-section of the anchor. The steel sleeves in the concrete havesubstantially coincident coefficients of thermal expansion and therelatively thin steel sleeve is generally at the same temperature as theconcrete so that thermal stresses are minimized. Since the sleeves actas force-transmitting columns, shear stresses of the slab parallel tothe concrete plates have little effect and, since the sleeve alwaysextend perpendicular to the concrete plates, the sleeves are tortionallyrigid and can take up the necessary stresses when the sandwich slab isrotated in its plane during mounting. It has already been observed thatthe slabs can be used to form facades, roofs and load-supportingwalkways and floors.

DESCRIPTION OF THE DRAWING The above and other objects, features andadvantages of the present invention will become more readily apparentfrom the following description, reference being made to the followingdrawing in which:

FIG. 1 is a cross-section perpendicular to the plane of sandwich slabaccording to the invention, illustrating the anchor assembly inelevation;

FIG. 2 is a view taken in the direction of arrow II and partly brokenaway;

FIG. 3 is a cross-section taken along the line Ill III of FIG. 1;

FIGS. 4 6 are perspective views illustrating other anchor sleevesaccording to the invention;

FIG. 7 is a perspective view showing another assembly using an anchorsleeve according to the invention; and

FIG. 8 is a plan view showing the structural member of the presentinvention.

SPECIFIC DESCRIPTION The sandwich slab construction of the presentinvention may, as shown diagrammatically in FIG. 8, comprise a rearconcrete slab I03 having a mat 106 of reinforcing rod embedded thereinand of generally rectangular configuration. The concrete plate 103 iscoextensive with a slab or plate of cellular synthetic resin asrepresented at 102, this insulating layer of foamed polystyrene, forexample, being overlain by the upper plate 101 of concrete. The platesare interconnected by anchor sleeves generally represented at 104 atspaced locations, the anchor sleeve 104 being constituted as describedin connection with FIGS. 1 7.

Referring now to FIG. I, in which the anchor assembly is shown ingreater detail, it will be apparent that the reinforced concrete plate1, the insulating layer 2 of foamed synthetic resin, and the rearreinforced plate 3 constitute a sandwich slab. The concrete plates 1 and3 are anchored together by tubules or sleeves 4 provided at respectiveextremities with means for locking the sleeve to the respective concreteplates. In the embodiment illustrated in FIGS. 1 3, the lower concreteplate 3 is provided with a lattice work or mat 6' of reinforcing rod,the rod running parallel to the plane of the paper being represented atwhile the rods 6b run perpendicular tothe plane of the paper. The rods60' and 6b, therefore, define a lattice work in an interstice of whichthe sleeve 4 is seated. The mat has an effective thickness V (FIG. 1).

The means 5 at each end of the sleeve 4 may include rows 50 and Sb ofperforations which are angularly staggered and are spaced axially by adistance U V, each hole being paired with a diametrically opposite holeso that rods 7 may be passed through the holes and project laterally toengage the rods of the mats 6. The rods 7 may be lengths of reinforcingrod and project to a distance W X where X is the spacing of a rod of themat from the tube 4. It has been found to the advantageous to have theprojecting portions of the rods 7 approximate the diameter D of thetube. In practice, 0.5 D S W 5 1.5 D. The rods 7 have diameters D" whichare slightly less than the diameters d of the holes 50 and 5b. A similaranchorage of the tube 4 to the upper concrete plate is provided. Thesleeve 4 may have a thickness S (FIG. 3) which is less than D and aminor fraction of the diameter D of the tube, this diametercorresponding approximately to the thickness T or T of the concreteplates. In general, insulating layer 2 will have a thickness R rangingbetween 0.3Tand 1.5 T. The interior of the sleeve 4 is provided with aplug 8 of the foamed synthetic resin constituting the layer 2 andpunched out when the tube 4 is driven into the insulat ing layer. Tofacilitate the punching of this plug, an edge of the tube can bechamfered.

In FIGS. 4 7, other tube structures have been illustrated and it will beunderstood that, in each case, the structure may be used interchangeablywith the tube 4 and in the system illustrated in FIG. 8. In FIG. 4, forexample, the cylindrical tube 204 is provided with formations generallyrepresented at 205 at opposite extremities for anchoring to the concreteplates. These formations include the ports 205a and 205b as described inconnection with tube 4, and crenelated extremities having tongues 2050which may be bent outwardly as shown in dot-dash lines to engage theconcrete or, as described in connection with FIG. 7, to lodge behind themats. In the system of FIG. 5, the tube 304 has a rectangularcross-section (square) and the rows 305a and 3051) of holes permit twoor more rods 307 to extend in each direction as part of the anchor meansrepresented generally at 305. The tube 404 illustrated in FIG. 6 is ofconical configuration and likewise has means 405 in the form of rows ofholes for anchoring the tube in the concrete slab. In FIG. 7, there isshown a modification wherein outwardly bent tabs 505b to lie on theother side of each concrete mat. The hexagonal tube 504 of FIG. 7 isbent from sheet metal and the ends are joined at 5040.

The improvement described and illustrated is believed to admit of manymodifications within the ability of persons skilled in the art, all suchmodifications being considered within the spirit and scope of theinvention except as limited by the appended claims.

What is claimed is:

l. A sandwich slab comprising a pair of spaced generally parallelconcrete plates, a layer of insulation sandwiched vbetween said plates;at least one tubular anchor extending through said layer of insulationand lodged at opposite extremities in said concrete plates, said tubularanchor being provided at least at one extremity lodged in a respectiveplate with means positively anchoring the plate thereto, said meansincluding at least two pairs of opposing holes formed in said tubularanchor and a respective rod traversing the holes of each of said pairsand projecting transversely from the tubular anchor into the concrete ofthe respective plates, the pairs of holes and rods being relativelystaggered angularly; and a latticework of reinforcing bars in the plateinterengaging with said rods.

2. A sandwich slab comprising a pair of spaced generally parallelconcrete plates, a layer of insulation sandwiched between said plates,and at least one tubular anchor extending through said layer ofinsulation and lodged at opposite extremities in said concrete plates,said tubular anchor being provided at each extremity lodged in arespective plate with means positively anchoring the plate thereto, saidmeans including holes formed in said tubular anchor and a rod traversingsaid holes and projecting transversely from the tubular anchor into theconcrete of the respective plates, each of said plates having arespective lattice-work of reinforcing bars, said rod engaging saidbars, said tubular anchor being provided at each extremity with a pairof axially spaced rows of such holes and the holes of the rows of eachpair being staggered angularly with respect to the holes of the otherrow of the respective pair, at least one such rod traversing the holesof each row and said rods lying on opposite sides of the respectivelatticework.

3. The slab defined in claim 2 wherein said tubular anchor has theconfiguration of a conic section.

4. The slab defined in claim 3 wherein said tubular anchor is conical.

5. The slab defined in claim 2 wherein said tubular anchor has across-section corresponding to a regular polygon.

6. The slab defined in claim 2, further comprising a plug of thermalinsulation received in said tubular anchor.

1. A sandwich slab comprising a pair of spaced generally parallelconcrete plates, a layer of insulation sandwiched between said plates;at least one tubular anchor extending through said layer of insulationand lodged at opposite extremities in said concrete plates, said tubularanchor being provided at least at one extremity lodged in a respectiveplate with means positively anchoring the plate thereto, said meansincluding at least two pairs of opposing holes formed in said tubularanchor and a respective rod traversing the holes of each of said pairsand projecting transversely from the tubular anchor into the concrete ofthe respective plates, the pairs of holes and rods being relativelystaggered angularly; and a latticework of reinforcing bars in the plateinterengaging with said rods.
 2. A sandwich slab comprising a pair ofspaced generally parallel concrete plates, a layer of insulationsandwiched between said plates, and at least one tubular anchorextending through said layer of insulation and lodged at oppositeextremities in said concrete plates, said tubular anchor being providedat each extremity lodged in a respective plate with means positivelyanchoring the plate thereto, said means including holes formed in saidtubular anchor and a rod traversing said holes and projectingtransversely from the tubular anchor into the concrete of the respectiveplates, each of said plates having a respective lattice-work ofreinforcing bars, said rod engaging said bars, said tubular anchor beingprovided at each extremity with a pair of axially spaced rows of suchholes and the holes of the rows of each pair being staggered angularlywith respect to the holes of the other row of the respective pair, atleast one such rod traversing the holes of each row and said rods lyingon opposite sides of the respective latticework.
 3. The slab defined inclaim 2 wherein said tubular anchor has the configuration of a conicsection.
 4. The slab defined in claim 3 wherein said tubular anchor isconical.
 5. The slab defined in claim 2 wherein said tubular anchor hasa cross-section corresponding to a regular polygon.
 6. The slab definedin claim 2, further comprising a plug of thermal insulation received insaid tubular anchor.